docs: def specificity(Ntn, Nfp, eps=numpy.spacing(1)):
      """Specificity
  
      Wikipedia entry https://en.wikipedia.org/wiki/Sensitivity_and_specificity
  
      Parameters
      ----------
      Ntn : int >= 0
          Number of true negatives.
  
      Nfp : int >= 0
          Number of false positives.
      
      eps : float
          eps.
          Default value numpy.spacing(1)
  
      Returns
      -------
      specificity: float
          Specificity
  
      """
  
      return float(Ntn / (Ntn + Nfp + eps))